Sky News Australia’s YouTube channel has published more than 9,000 comments mostly celebrating and mocking the shooting of a Black Lives Matter activist in Britain who is fighting for her life.

The racist and violent comments, which could be described as hate speech, appear below a short video news report uploaded on Monday about the activist Sasha Johnson. Johnson remains in a critical condition after sustaining a gunshot wound to her head in an incident in south London.

“Damn, every once in a while I read something that makes me want to celebrate,” one typical commentator on Sky’s YouTube channel wrote. “Hope she enjoys being a vegetable.”

Another person commented: “When you preach violence this is what you get. Don’t feel sorry for any of these criminals!!”

Sky News and YouTube were alerted to the comments on Monday but they remained online days later. A spokeswoman for Sky News told Guardian Australia the channel was not responsible for the publication of the comments.

“Sky News Australia published a brief news report on the recent shooting of Sasha Johnson,” a spokesperson said. “Sky News Australia is not the author of user comments on the YouTube platform. We suggest you direct your inquiries to Google.”

There are barely any supportive comments about Johnson, a 27-year old mother of three, and many Sky News viewers used the shooting as a vehicle to attack the Black Lives Matter movement, the defund the police movement and the black community in general.

The comments also included calls for violence against politicians, including murder.

YouTube, owned by Google, told Guardian Australia it was reviewing the video and any comments against its community guidelines. It said “uploaders”, in this case Sky News, had the ability to delete or disable comments.

“We take the safety of our users very seriously and have strict policies that prohibit hate and harassment on YouTube, including content promoting violence or hatred against individuals or groups,” a spokesperson said.

“Our community guidelines apply to videos and comments alike. Any flagged content found to violate our policies is removed from YouTube immediately.”

After this story was published on Thursday, YouTube advised Guardian Australia they were now “actively” removing comments that violated community guidelines.

“We are removing comments that are violative of our policies and will continue to do so as we keep monitoring the comments on the video,” a spokeswoman said.

The former Labor prime minister, Kevin Rudd, wrote to the acting managing director of Google Australia & New Zealand, Caroline Rainsford, on Monday to ask if YouTube would review its commercial arrangement with Sky News in light of the shocking comments.

The letter was copied to the News Corp Australasia executive chairman, Michael Miller, who has responsibility for Sky News.

Rudd told the media diversity inquiry in February that Rupert Murdoch’s Sky News would radicalise politics in Australia within a decade just as Fox News had undermined democracy in the United States.

“While this particular video is a purely factual report, lasting only 39 seconds, the subscribers’ comments beneath it illustrate how Sky News’ most popular videos are cultivating this far-right echo-chamber,” Rudd wrote to Google.

“At the time of writing, the 7,000 comments beneath this video are flooded – by an unspeakable margin – with expressions of elation and support for this act of violence. When viewers of Australian news content are jubilant at the news of a young woman being shot in the head, something is seriously wrong.

“However, media proprietors such as YouTube and Sky News Australia have a responsibility not to promote extremism merely because it is profitable to do so. I note that Google has, since at least 2019, had a commercial arrangement with Sky News to distribute their content via YouTube.”

Rudd asked Google how much YouTube paid Sky News; why it published videos which “inspire contempt for human life” and if it was “at all concerned that its platform is being used by Sky News to radicalise Australians in this way”.